docs: def create_instance(self, nova, image_name, instance_name, flavor):
          """Create the specified instance."""
          self.log.debug('Creating instance '
                         '({}|{}|{})'.format(instance_name, image_name, flavor))
          image = nova.glance.find_image(image_name)
          flavor = nova.flavors.find(name=flavor)
          instance = nova.servers.create(name=instance_name, image=image,
                                         flavor=flavor)
  
          count = 1
          status = instance.status
          while status != 'ACTIVE' and count < 60:
              time.sleep(3)
              instance = nova.servers.get(instance.id)
              status = instance.status
              self.log.debug('instance status: {}'.format(status))
              count += 1
  
          if status != 'ACTIVE':
              self.log.error('instance creation timed out')
              return None
  
          return instance